Hydrogen liquefaction system and method

Abstract

A system and method for liquefying a hydrogen gas feed stream uses a pre-cooling refrigerant for pre-cooling the feed stream, where the pre-cooling refrigerant is compressed, cooled and then separated to provide high pressure mixed refrigerant vapor and liquid streams. The high pressure vapor stream is cooled and directed to a cold vapor separator where cold separator liquid and vapor streams are formed. The cold separator vapor stream is cooled and expanded to provide a pre-cool refrigeration stream in a heat exchanger system. The high pressure pre-cooling refrigerant liquid and cold separator liquid streams are cooled and expanded and directed to the pre-cool refrigeration stream. A high pressure primary refrigerant steam, after compression and cooling, is further cooled in the heat exchanger system and then expanded using warm and cold expanders, with the resulting expanded primary refrigerant streams used to liquefy the pre-cooled hydrogen feed stream via heat exchange in the heat exchanger system.

What is claimed is: 
     
       1. A system for liquefying a hydrogen gas feed stream comprising:
 a. a heat exchanger system having a feed gas inlet configured to receive the hydrogen gas feed stream, a product outlet, a cooling passage in fluid communication with the feed gas inlet and the product outlet, a primary refrigerant feed passage, a primary refrigeration passage, a pre-cooling refrigeration passage, a high pressure vapor cooling passage, a cold separator vapor cooling passage, a cold separator liquid cooling passage and a high pressure liquid cooling passage; 
 b. a primary refrigerant compression system configured to direct a conditioned primary refrigerant to the primary refrigerant feed passage; 
 c. a warm expander in fluid communication with the primary refrigerant feed passage, said warm expander having a warm expander outlet in fluid communication with the primary refrigerant compression system; 
 d. a cold expander in fluid communication with the primary refrigerant feed passage, said cold expander having a cold expander outlet in fluid communication with the primary refrigeration passage; 
 e. said cooling passage configured so that hydrogen therein is cooled and liquefied by countercurrent heat exchange with primary refrigerant in the primary refrigeration passage; 
 f. said primary refrigerant compression system configured to receive, compress and cool vaporized primary refrigerant from the primary refrigeration passage so that a conditioned primary refrigerant is provided; 
 g. a pre-cooling mixed refrigerant compression system including a pre-cooling compressor configured to receive and compress a pre-cooling mixed refrigerant stream and to direct a compressed mixed refrigerant stream to a pre-cooling aftercooler, said pre-cooling aftercooler having an aftercooler outlet in fluid communication with a high pressure separation device having a mixed refrigerant vapor outlet configured to direct mixed refrigerant vapor to the high pressure vapor cooling passage and a mixed refrigerant liquid outlet configured to direct mixed refrigerant liquid to the high pressure liquid cooling passage; 
 h. a cold vapor separator having an inlet configured to receive fluid from the high pressure vapor cooling passage, said cold vapor separator having a cold vapor separator vapor outlet configured to direct vapor to the cold separator vapor cooling passage and a cold vapor separator liquid outlet configured to direct liquid to the cold separator liquid cooling passage; 
 i. a first expansion device configured to receive and expand fluid from the cold separator vapor cooling passage and to direct expanded fluid to the pre-cooling refrigerant passage; 
 j. said high pressure liquid cooling passage and said cold separator liquid cooling passage each in fluid communication with the pre-cooling refrigeration passage; 
 k. said cooling passage configured so that hydrogen therein is cooled by countercurrent heat exchange with pre-cooling mixed refrigerant in the pre-cooling refrigeration passage. 
 
     
     
       2. The system of  claim 1  wherein the heat exchanger system includes a warm heat exchanger and a cold heat exchanger. 
     
     
       3. The system of  claim 2  wherein streams flowing through the warm heat exchanger are above approximately 80 K and streams flowing through the cold heat exchanger are below approximately 80 K. 
     
     
       4. The system of  claim 2  wherein the pre-cooling refrigeration passage is formed solely in the warm heat exchanger and the primary refrigeration passage is formed in both the cold and warm heat exchangers. 
     
     
       5. The system of  claim 1  wherein the primary refrigerant is selected from the group consisting of hydrogen, helium, a mixture of neon and helium, a mixture of neon, helium and hydrogen and a mixture of hydrogen and helium. 
     
     
       6. The system of  claim 5  wherein the pre-cooling mixed refrigerant stream includes a component selected from the group consisting of nitrogen, methane, ethylene, ethane, propane, pentanes, isobutane and n-butane. 
     
     
       7. The system of  claim 1  wherein the pre-cooling mixed refrigerant stream includes a component selected from the group consisting of nitrogen, methane, ethylene, ethane, propane, pentanes, isobutane and n-butane. 
     
     
       8. The system of  claim 1  wherein the heat exchanger system includes a first primary refrigeration passage and the primary refrigeration passage is a second primary refrigeration passage and the warm expander is configured to receive a first portion of primary refrigerant from the primary refrigerant feed passage and to direct an expanded first portion of the primary refrigerant to the first primary refrigeration passage and the cold expander is configured to receive and expand a second portion of primary refrigerant that has been further cooled in the primary refrigerant feed passage and direct an expanded second portion of the primary refrigerant to the secondary primary refrigeration passage. 
     
     
       9. The system of  claim 8  wherein the primary refrigerant compression system includes a first compressor configured to receive a vapor stream from the second primary refrigeration passage of the heat exchanger system, a first aftercooler configured to receive fluid from the first compressor, a second compressor configured to receive fluid from the first aftercooler and a second aftercooler configured to receive fluid from the second compressor, said second aftercooler in fluid communication with the primary refrigerant feed passage of the heat exchanger system and wherein the second compressor is configured to receive a vapor stream from the first primary refrigeration passage of the heat exchanger system. 
     
     
       10. The system of  claim 8  wherein the primary compression system is configured to combined vaporized primary refrigerant streams from the first and second primary refrigeration passages prior to the first compression stage. 
     
     
       11. The system of  claim 8  wherein the heat exchanger system includes a warm heat exchanger and a cold heat exchanger and wherein the first and second primary refrigeration passages pass solely through the cold heat exchanger, exit the cold heat exchanger and direct vapor to the primary refrigerant compression system and wherein the pre-cooling refrigeration passage passes solely through the warm heat exchanger. 
     
     
       12. The system of  claim 8  wherein the warm expander and the cold expander are turbines that power conditioning compressors that are configured to receive and compress a primary refrigerant vapor stream from the second primary refrigeration passage and to direct compressed vapor to the primary refrigerant compression system. 
     
     
       13. The system of  claim 1  further comprising catalyst in the cooling passage of the heat exchanger system so that conversion of hydrogen from ortho to para states is accomplished as hydrogen is cooled and/or liquefied in the cooling passage. 
     
     
       14. The system of  claim 1  further comprising a series of warm expanders, including the warm expander, in fluid communication with the primary refrigerant feed passage, said series of warm expanders in fluid communication with the primary refrigerant compression system and a series of cold expanders, including the cold expander, in fluid communication with the primary refrigerant feed passage, said series of cold expanders in fluid communication with the primary refrigeration passage. 
     
     
       15. The system of  claim 14  wherein the warm series of expanders and the cold series of expanders include turbines. 
     
     
       16. The system of  claim 1  further comprising:
 l. a second expansion device configured to receive and expand fluid from said high pressure liquid cooling passage, said second expansion device in fluid communication with the pre-cooling refrigeration passage; 
 m. a third expansion device configured to receive and expand fluid from said cold separator liquid cooling passage, said third expansion device in fluid communication with the pre-cooling refrigeration passage. 
 
     
     
       17. The system of  claim 1  wherein the warm expander is configured to receive a first portion of primary refrigerant from the primary refrigerant feed passage and the warm expander and the cold expander are turbines that power compressors and further comprising:
 l. an intermediate cooling passage within the heat exchanger system configured to receive and cool fluid from the warm expander and to direct fluid to the cold expander, wherein said cold expander outlet is configured to direct an expanded first portion of primary refrigerant to the primary refrigeration passage; 
 m. a primary feed expansion device configured to receive and expand a second portion of primary refrigerant that has been further cooled in the primary refrigerant feed passage and direct an expanded second portion of the primary refrigerant to the heat exchanger system. 
 
     
     
       18. The system of  claim 17  further comprising:
 n. a supplemental cold expansion device configured to direct fluid to the primary refrigeration passage; 
 o. a supplemental intermediate cooling passage within the heat exchanger system configured to receive and cool fluid from the cold expander and to direct fluid to the supplemental cold expansion device. 
 
     
     
       19. The system of  claim 1  wherein the warm expander is a first warm expander configured to receive a first portion of primary refrigerant from the primary refrigerant feed passage and further comprising:
 l. a second warm expander configured to receive a first portion of fluid from the first warm expander and to direct fluid to the primary refrigeration passage; 
 m. an intermediate cooling passage within the heat exchanger system configured to receive and cool a second portion of fluid from the first warm expander and to direct fluid to the cold expander; 
 n. a primary feed expansion device configured to receive and expand a second portion of primary refrigerant that has been further cooled in the primary refrigerant feed passage and direct an expanded second portion of the primary refrigerant to the heat exchanger system. 
 
     
     
       20. The system of  claim 1  wherein the heat exchanger system includes a first primary refrigeration passage and the primary refrigeration passage is a second primary refrigeration passage, the warm expander is configured to receive a first portion of primary refrigerant from the primary refrigerant feed passage and direct fluid to the first primary refrigeration passage and the cold expander is a first cold expander configured to receive a second portion of primary refrigerant from the primary refrigerant feed passage and further comprising:
 l. a second cold expander configured to direct fluid to the second primary refrigeration passage; 
 m. an intermediate cooling passage within the heat exchanger system configured to receive and cool fluid from the first cold expander and to direct fluid to the second cold expander; 
 n. a primary feed expansion device configured to receive and expand a third portion of primary refrigerant that has been further cooled in the primary refrigerant feed passage and direct an expanded third portion of the primary refrigerant to the heat exchanger system. 
 
     
     
       21. The system of  claim 1  wherein the heat exchanger system includes a first primary refrigeration passage and the primary refrigeration passage is a second primary refrigeration passage and the warm expander is configured to receive a first portion of primary refrigerant from the primary refrigerant feed passage and further comprising:
 l. an intermediate expander configured to receive a second portion of primary refrigerant from the primary refrigerant feed passage and to direct an expanded second portion of primary refrigerant to the first primary refrigeration passage; 
 m. an intermediate cooling passage within the heat exchanger system configured to receive and cool fluid from the warm expander and to direct fluid to the cold expander, wherein said cold expander outlet is configured to direct an expanded first portion of primary refrigerant to the second primary refrigeration passage; 
 n. a primary feed expansion device configured to receive and expand a third portion of primary refrigerant that has been further cooled in the primary refrigerant feed passage and direct an expanded third portion of the primary refrigerant to the heat exchanger system. 
 
     
     
       22. The system of  claim 1  wherein the heat exchanger system includes a first primary refrigeration passage and the primary refrigeration passage is a second primary refrigeration passage, the warm expander is a first warm expander configured to receive a first portion of primary refrigerant from the primary refrigerant feed passage and the cold expander is configured to receive a second portion of primary refrigerant from the primary refrigerant feed passage and direct an expanded second portion of primary refrigerant to the first primary refrigeration passage and further comprising:
 l. a second warm expander configured to direct fluid to the first primary refrigeration passage; 
 m. an intermediate cooling passage within the heat exchanger system configured to receive and cool fluid from the first warm expander and to direct fluid to the second warm expander; 
 n. a primary feed expansion device configured to receive and expand a third portion of primary refrigerant that has been further cooled in the primary refrigerant feed passage and direct an expanded third portion of the primary refrigerant to the heat exchanger system. 
 
     
     
       23. The system of  claim 1  wherein the heat exchanger system includes a warm heat exchanger and a cold heat exchanger and wherein the heat exchanger system includes a first primary refrigeration passage solely in the cold heat exchanger and the primary refrigeration passage is a second primary refrigeration passage solely in the cold heat exchanger and the warm expander is configured to receive a first portion of primary refrigerant from the primary refrigerant feed passage and to direct an expanded first portion of the primary refrigerant to the first primary refrigeration passage and the cold expander is configured to receive and expand a second portion of primary refrigerant that has been further cooled in the primary refrigerant feed passage and direct an expanded second portion of the primary refrigerant to the secondary primary refrigeration passage and wherein said primary refrigerant compression system is configured to receive, cold compress and cool vaporized primary refrigerant from the first and second primary refrigeration passages so that a conditioned primary refrigerant is provided. 
     
     
       24. A method for liquefying a hydrogen gas feed stream comprising the steps of:
 a. pre-cooling the hydrogen gas feed stream using a mixed refrigerant by:
 i) compressing and cooling a mixed refrigerant stream to form a high pressure mixed refrigerant stream; 
 ii) separating the high pressure mixed refrigerant stream to form a high pressure mixed refrigerant vapor stream and a high pressure mixed refrigerant liquid stream; 
 iii) cooling the high pressure mixed refrigerant vapor stream in a heat exchanger, to form a mixed phase stream; 
 iv) separating the mixed phase stream with a cold vapor separator, to form a cold separator vapor stream and a cold separator liquid stream; 
 v) condensing the cold separator vapor stream and flashing, to form a cold temperature refrigerant stream; 
 vi) cooling the high pressure mixed refrigerant liquid stream in the heat exchanger, to form a cooled high pressure mixed refrigerant liquid stream; 
 vii) cooling the cold separator liquid stream to form a cooled cold separator liquid stream and combining the cooled cold separator liquid stream with the cooled high pressure mixed refrigerant liquid stream, to form a middle temperature refrigerant stream; 
 viii) combining the middle temperature refrigerant stream and the cold temperature refrigerant stream to form a combined pre-cool refrigerant stream; 
 ix) thermally contacting the hydrogen gas feed stream with the combined pre-cool refrigerant stream in the heat exchanger to form a pre-cooled hydrogen gas feed stream; 
 
 b. liquefying the pre-cooled hydrogen gas feed stream using a primary refrigerant by:
 i) compressing and cooling a first vaporized primary refrigerant and a second vaporized primary refrigerant to form a high pressure primary refrigerant; 
 ii) expanding the high pressure primary refrigerant in a warm expander to form a first expanded primary refrigerant; 
 iii) expanding the high pressure primary refrigerant in a cold expander to form a second expanded primary refrigerant; 
 iv) thermally contacting the pre-cooled hydrogen gas feed stream with the first and second expanded refrigerants to form first and second vaporized primary refrigerants and a liquefied hydrogen stream. 
 
 
     
     
       25. The method of  claim 24  wherein the primary refrigerant is selected from the group consisting of hydrogen, helium and a mixture of hydrogen and helium.